Calculating device



Jan. 27, 1942. G. H. GORDON CALCULATING DEVICE Filed Alig. 4, 1959 4 Sheets-Sheet l INVENTOR 6:011? 15'. 6010 021 BY Jan. 27, 1942.

Filed Aug. 4,1939

4 Sheets-Sheet 2 m I w .IIIII "um I g r I mum n N &\ l INVENTOR g -||||mn 6:011? 15. fiardon ATT RNEY-S Jan. 27, 1942.

G. H. GORDQN 2,271,508

CALCULATING DEVICE 4 Sheets-Sheet 3 Filed Aug. 4, 1939 (1 10!!! 11 fiordon ATT RNEY G. H. GORDN. 2,271,508

CALCULATING DEVICE Filed Aug. 4, 1939 4 Sheets-Sheet 4 INVENTOR fieoge 1!. 0111021 A ORNEYS Jan. 27, 1942.

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' odds'on each horse.

Patented Jan. 27, 1942 UNITED. STAT CALCULATING DEVICE case H. Gordon, New'York, N. in, assignor, by mesne assignments, to Carter R. Leidy Application August 4,1930, Serial ue.-288,219

. v 9 Claims. This invention relates to calculating devices andhas particular reference to devices for to talizing bets, calculating odds and displaying totals and odds at race tracks.

Race track totalizers which have been. used heretofore are complicated mechanical and/or electrical mechanisms which include. large numbers of selector devices of the type commonly used in automatic telephone circuits as well as relays, gears and the like which render them extremely expensive to manuiacture and-maintain in operating condition. Complex as these mechanisms are, they require a large personnelto operate them or maintainthemin operating conclition and to calculate iromthe' totals obtained: by theoperation of the device the approximate .The present-invention has as an object the productionoi a calculating device by means of which the'grand total of amounts bet on a race, the total amount bet on each horse and the odds on each horse may be calculated without recourse to any manal or mental calculation on the part of the operator of the device. The. calculations are made automatically and during the period when the-bets are being placed;

I v Another object of the invention is to provide calculating devices which are capable of adding, subtracting, multiplying. and dividing, all of which functions are carried out substantially entirely electrically withoutthe necessity for pro- Other objects of the invention will be apparent from the following description of a typical form .of the device embodying the features of the invention.

In its broadest aspects the present invention utilizes the principles of the well-known Wheatstone bridge in that the calculating system for adding, subtracting. multiplying and dividing is a resistance circuit in which numerical values are represented by resistances of predetermined value. By increasing or decreasing the resistance in the circuit or circuits proportionately to the numerical values, one or more automatic resistance measuring devices located at near or remote points determine the total numerical value represented by the resistances at any instance.

More particularly the invention includes a counting mechanism bymeans of which the resistance in one arm of a resistance bridge circuit is increased in proportion to the sum or difference of numerical values that are to be determined while in another arm of the bridge the resistance is automatically varied in order to maintain it equal to the resistance in theflrst arm of the bridge. In response to this equalizing operatlon, indicators which'represent the total value oi the resistance in the second'arm are actuated and which upon proper calibration may inviding complicated arrangements of gears or Y other mechanical elements.

A further object of the invention is to provide electrical calculating devices which are accurate, rugged, unaffected by voltage variations and/or temperature change within comparatively wide limitations.

An additional object of the invention is to rovide calculating devices which are particularly suitable for use in parimutuel betting and which used without modification at racesin which the dicate directly the numerical value correspond,- ing, to the resistance in the first arm of the bridge or a value proportional to the exact resistance. This principle of operation may be readily utilized in such devices as adding machines and is particularly suitable for use in calculating machines for determining the amounts bet at race tracks and the odds of the various bets.

In a typical form of device, each betting station or, booth is provided with one or more devices which can, in step by step relationship and -are compact,- portable .and are capable of being number or betting-stations may .be widely varied a in accordance with the attendance at the track or the number of horses in the race. v

A further object 0! the invention is to provide registering mechanisms foruse with calculating machines which areactuated electrically.

in accordance with the amounts bet, vary the resistance in one arm of a resistance bridge circuit. The resistance bridge is initially balanced with respect to line contact or other inherent resistance in the circuit. As the resistance in the first arm or the bridge is varied, the amounts of current flowing in each arm become unequal and this inequality is utilized to actuate through a thermionic valve circuit an electrically driven mechanism which tends to increase or decrease A still further object of the invention is .to so theresistance in the second arm of the bridge and provide control mechanisms whereby such registers may be operated in response to inequalities in. voltages or resistance whereby substantially automatic operation of the registers'may be obtained.

thereb'yagain bring the bridge into balance.

The balancing means in turn may be utilized to actuate conventional indicating drums or to control circuits whereby indicating means may be displayed to indicate at each instant or at any predetermined time or interval, the values such as, for example, dollars or cents, or any other unit,

zeflpgesented by the resistances in the arms of the Resistance bridge circuits similar to that described gene'rally above may be likewise used to determine the ratios between the values of the resistances at each betting station or the amount bet upon each horse whereby the oddsmay be accurately calculated on each horse.

Likewise, by selectively unbalancing the bridge, ratios, for example, to effect a tax deduction on the total may be obtained.

Similar principles as will be pointed out hereinaiter may be utilized in order to provide add lng machines or other forms of calculating devices whereby ordinary commercial adding, sub-' actlmted registering or indicating mechanism which is responsive to variations in the resistance in the bridge circuit and thus can provide a visual indication of the values represented by the resistances in or ratios between the resistances in the bridge circuit. Additionally, the invention includes a novel resistance varying device or counting mechanism whereby resistances representing numerical values may be varied in the circuit.

For a better understanding oi the present invention, reference may be had to the accompanying drawings, in which:

Figure 1 is a wiring diagram oi a typical form of calculating machine utilizing two adding or betting units;

Figure 2 is a front view partly broken away of a typical form of device for varying theresistance in the bridge circuit in accordance with the amount to be added;

Figure 3 is a sectional view taken on line 3-3 of Figure 2;

Figure 4 is a sectional view taken on line 4-4 01' Figure 2;

Figure 5 is a plan view of a combined resistance varying and indicating device which may be used in conjunction with the circuit;

Figure 6 is a side view partly broken away of the device disclosed in' Figure 5';

Figure 7 is a diagrammatic circuit showing a circuit of a typical resistance varying and indicating device; and

Figure 8 is a wiring diagram of the electrical control for actuating the resistance varying and indicating device.

The electrical circuit disclosed in Figure 1 of the drawings illustrates a typical two-stage or two-booth betting totalizer in which bets may be placed upon two horses. In each of the booths I0 and H is provided resistance varying devices I2, ll, I4 and "with the resistance varying devices l2 and H being connected in series and torming.one'arm of a Wheatstone bridge A. The resistance increasing devices I! and I5 likewise are connected in series and form one arm of a resistance bridge B. Each of the resistance varying devices I2, l3, ll and I5 is adapted to have the resistance increased therein in steps in which each step may be considered equal, for example, to two dollars. Thus, for each two dollars bet at each of the stations the resistance can be increased by a predetermined fixed amount, for example 5 ohms, or any other predetermined amount, as may be desired, butin any event the value oi each dollar is represented in adeflnite resistance value.

Another opposed arm of the bridge A is former by a series 0! variable resistances IS, H, II anc I! which are adapted to be automatically varier' to maintain their total resistances equal to th! resistances in the devices l2 and H. An additional resistance 20 is connected in series with the resistances I6, H, II and Il in order is balance out the resistances of the lines 2| and 21 which connect the resistance devices l2 and H in the bridge circuit. In the third arm at the bridge are provided the parallel resistances 2i and 24 which are opposed in turn by a resistance 25 in the fourth arm of the bridge to equalize and balance the bridge. The resistance 24 may have a greater value than the resistance 23 so thai when connected in the circuit by means oi the switch 28 it eil'ects a deduction from the total resistance required in resistances ll, ll, II and I! to balance up the circuit. Therefore, by means of the resistance 24 it is possible to eflect a deduction on the total resistance corresponding to, for example, taxes on the betting or percentage deduction taken by the race track establishment. Current is supplied to the bridge circuit at opposite ends thereof and instead of a galvanometer ior determining whether or not the bridge is in balance, a thermionic valve circuit 21, which will be described in detail hereinafter, is provided for controlling electrical means for automatically' varying the values oi the resistances i6, i1, Hand-l9.

-Resistances l6, II, It and It may vary in value to correspond to tenths oi a dollar, dollars, tens and hundreds 01 dollars, respectively, so that if actuated sequentially, and step by step, any value can be produced ranging from 10 to $999.90, thus giving the device great flexibility and rendering it capable oi responding equally to variations in the resistance at the resistance varying devices and II. It should be understood that while only four such variable resistances l6, l1, l8 and I! are disclosed that a greater number may be provided in accordance with the top numerical value that may be desired. Accordingly, suflicient number of banks of resistances may be used to provide a reading as high as may be desired, for example, one hundred thousand or one million dollars.

The resistance varying devices i3 and I! are connected in the bridge circuit B in an identical way and in this circuit the various tenths, units, tens and hundreds banks oi resistances 2|, 2!, 30 and ii are provided for equalizing the resistances in the arms of the bridge.

In order to obtain a registration of the total amount bet upon each horse, a second bridge circuit is provided in which resistances oi equal value to the resistances I6, I1, I8, is, 2|, 2!, II

and ti are provided and connected in series to form one arm of a bridge circuit C. The resistances 32, I2, 34, ll, 3, 31, 38 and II are varied simultaneously and equally with the in series to form the opposed arm 01' the resistance bridge circuit C and are adapted to be varied sequentially in order to provide a total resistance in this arm of the bridge equal to the total resistance as introduced by the resistancesH-ll, inclusive. The resistances It to 40, respectively.

correspond to tenths, units, hundreds, thousands and one hundred thousands and are adapted to be varied sequentially to represent from zero to" '999,999'.9. A device l'l'which is responsive to the sum of the resistances interposed in the circuits A a-nd B byjvarying theresistance in the betting booths by the devices II, l3, I8 and i8.

viding' a plurality of resistance varying devices "similar to devices l2,-l3, II and it which vary in In order to obtain the odds on. the two horses 7 represented in-the booths I2 and I l and I3 and I8, respectively, additional bridges D and -E are provided. In the resistance bridge vD one arm of the bridge is represented by resistances ll, 48,

88' and 88 which correspond in value, at any instant, to the resistances 28, 28, 80 and IL, In

the samearm of the bridge, but on opposite side a of the voltage responsive device 21, are the resistances 8|, 82,83 and 84 which correspond in value, at any instant, to the value of the resistances l8, l1, l8 and i8. In the opposite arm of" thebridge D' are a series of automatically actuated resistances 88, 58', 81,58 and 88 which may be; variedunder the control of the voltage re- "sponsive device 21 tov indicate the ratio of the Value of the resistances 41 to 58, inclusive, to the rat-lo. of the resistances to 84, inclusive, thereby giving directly the profit to beobtalned upon a one dollar bet. If it is desired to cause the resistances SS-SQ, inclusive, to represent the rate on, for example, a two dollar bet the resistance 88 may .be given an appropriate value in accordance with the well-known formula. for W fl ne bridges inorder to'double or double and add the amount bet to the odds indication.

The bridge E is similar to the bridge D with of resistance interposed, in. the circuit by the variable resistances 88, 10, II, I! and I! in the other adjustable and ofv the bridge. I

It should be noted that each of the odds an the resistancesteps' fro'mone through nine and are provided with app priate resistance values from those corresponding 150 hi or a fraction thereof'to 10, 100, 1000, and so for h. Likewise, when large resistance values may accumulate in the bridge, it is possible to start witha high resistance value, in the bridge circuit and deduct resistance so that at the end of an accumulating operation, the total resistance is lowered and the sensitivity of the bridge increased.

with devices of the type described above and at races in which a greater number of horses than three are entered, it is possible to calculate the odds for the horses to'show. Means may be provided in the bridge circuits, corresponding to A and B bridge circuits, for reducing the total toone-third of their. value, by introducing a resistance of suitable value into the bridge circuits.

For example, if there were six horses in the race,

three horses would be represented in the show odds. The total values on the remaining horses may be reduced to one-third value and the total bet on each of the. winning horses is separately balanced against one third oi the total of the amount bet on the horses which have not won. The resulting ratio gives the show odds on each of the winninghorses.

The resistance varying or betting devicesmay take various forms, one. 9! which, the preferred form, is disclosed in Figures 2 to 4, As shown in Figure '4, each device I2 to I! includes a framework Il through which projects a key 15 that is normally retained in an upward position by means of a spring 18 interposed between the top of the framework I4 and a collar 'l'l ,onthe key stem 18. The key stem is pivotally connected to a shaft 18 which is rotatablymounted in a yoke .40 the exception that the relationship of the re- 88. The yoke" is pivotally supported on a shaft I 8| which projects through thefsideelements of the frame '14 and is rotatable therein. On opposite ends of the, shaft 18 are fixed pawl members 82 and 88 which are adapted to cooperate grand totals, bridges c, n and E are controlled by dummy banks of resistors which are separate and distinct from the resistors I848, inclusive,

or 28, 2 9, 38 and II which are associated with the bridges A and B, Therefore, there is no necessity for providing switches or other means which might resultin inaccuracy in operation-of the bridge since each bridge operates independently I of every other bridge. I

In order to assure the accuracy of the various bridge circuits and maintain the desired sensitivity, the bridge circuits may be supplied with current which remains constant despite .variation of the resistance in the bridge. This may be accomplished by connecting a ballast resistance 13a in series with the source of current supply, asillustrated in Figure l in bridge circuit additional stations may be provided by merely increasing the number of resistance bridge cir-" Likewise, this mechanism can be utilized quite readily as an adding, ma-

cuits in the device.

chine by eliminating the odds circuit and by pro- "corresponding 'to' some numerical value.

with disc elements 84 and which are rotatably mounted on the shaft 8|. Each of the discs 84 and 88 is provided with ratchet teeth.

The disc 84 is of somewhat greater diameter than the disc 85 and is provided with a series of ratchet teeth 88, all of which are of equal depth, except one, 8611, whichis of greater depth. The disc 88 is likewiseprovided with ratchet teeth 81 which are of lesserheight than the base of the ratchet teeth 86 on disc 84 but are of the same depth or distance'from' theshaft 8! as the bottom of the ratchet tooth 86a ondisc 84. Therefore, upon depressionTof the key 15, the pawl 82 will engage behind a'tooth. 86 on the disc 84 and rotateit one step. However, because the teeth 81 on disc 85 are of lesser height than the teeth 88, disc 85 will not be rotated until the tooth 86a is engaged by the pawl 82. When this occurs, the pawl 83 can move into engagement with one of the teeth 81 and rotate the disc 85 one step. Thus, if there are ten teeth on disc 84 and an equal number of teeth on disc 85, it will require ten complete revolutions of disc 84 to rotate disc 85 one complete revolution.

The disc 84, as illustrated, is provided with a series of nine fixed resistances, each of a value Thus, each of the resistances 88 may have a value of 5 fohms and may represent two dollars or one dollar, as desired, and inasmuch as they are conthat may be interposed by rotation of the disc will be 45 ohms. Each of the resistances is electrically connected to, a commutator segment 00 which is disposed on the inner face of the disc 0|. An annular commutator segment 90 is disposed concentrically within the commutator segments 0! and is connected at all times with one of the commutator segments 00 by means of a commutator brush II of split form having one finger I! continuously engaging the commutator ring 00 and another finger 00 engaging one of the commutator segments 89. The disc member I! is similarly constructed with the exception that the resistances 04 have a value of ten times the value of the resistances 00. Thus, assuming that the value of the resistances I0 is ohms, as the disc I0 is rotated step by step, each step will introduce an additional 50 ohms into the circuit so that with this construction a total of 99 steps introducing a total of 495 ohms into the circuit may be taken before both of the devices are rotated to zero position, when the brush finger 03 contacts the blank segment 95 which introduces 'no resistance into the circuit. with this construction, it is thus possible to start with an initial resistance equivalent to zero in so far as the bridge circuit is concerned and vary it through ninety-nine steps to a maximum resistance. It will, be understood that the number of commutator segments may be varied widely and that a greater or lesser number of resistances may be provided as may be desired and that the number of discs like 04 and 00 may also be varied to permit a greater or lesser number of steps to be introduced by actuation of a single key. Thus, this construction may be widely varied without departing from the basic construction.

In order to return the discs to zero resistance position, the shaft II may be provided with a cam element I! which upon rotation in counterclockwise direction, as viewed in Figure 4, will engage a pawl 01 pivotally mounted on the inner face of each of the discs 04 and 05, thus permitting rotation of the discs back to the starting or initial position.

Retrograde turning of' the discs 04 and I5 is avoided by mean of spring fingers 81 which engage the teeth 01 and 00 of the discs 05 and 04, respectively.

As indicated above, the resistances I0, I], I0

and I0 as well as the associated resistances in the bridge circuits C, D and E, the resistances in the bridge circuit B and associated resistance are varied electrically in order to maintain the various bridge circuits in balance. In Figures 5 to 7 are disclosed a typical form of'device and a circuit for varying these resistances as well as indicating numerical values corresponding to the resistances or the ratios of the resistances in the bridge circuits.

In Figure 5 is disclosed a resistance varying device which consists of a frame 00 on which is mounted a reversing motor 9! which through reduction gears I00 drives a main drive shaft IOI which is rotatably mounted in the sides oi the frame 00. Fixed to the shaft IN is a disc member III which is provided with a plurality of protuberances I03 exceeding by one the number of fixed resistances I which are mounted on one side of the irame 00. The resistances I04 are connected in series and their individual and total values may correspond to the value of any of the variable resistances in the bridge circuits A, B. C, D and E, for example, the individual and total resistances oi the variable resistance II in bridge circuit A. Each of these resistances is electrically connected to a commutator segment I05 on the inner face of the face plate I00, which is engaged by a switching brush I0l carried by the disc I02. The brush I01 is provided with a finger I00 which engages a commutator ring III also carried by the disc I02 and thus aiiords an electrical connection between these two elements. A suitable contact brush, not shown, may also form an electrical connection between the commutator segment 95, so that upon rotation of the disc 04 the resistances i0 are successively connected in series. The switching brushes I" may be connected in series so that the resistances-interposed by rotation of the discs .84 and I0 are accumulative. Thus, as the disc I02 rotates, It progressively increases the resistance in the bridge circuit in a step by step fashion and in proportion to the value of the resistances Ill.

Mounted on the back plate H0 of the frame II are the switches III and H2. The switch III cooperates with a protuberance H0 on the disc I02 so that the switch H2 is closed once during a short interval as the protuberance I0 passes from 9 to 0 position for each complete revolution of the disc I02. The switch III is normally closed but is adapted to be opened to break the circuit when one of the protuberances I03 comes in contact with one of th element of the switch III as the disc moves from one portion to the next. Thus the switch III is adapted to be opened, in the form of the invention illustrated, ten times during each revolution of the disc I02. Relerring now to Figure 7 which illustrates the electrical connections between three of the devices shown in Figures 5 and 6, it will be noted that the motor 99 and the other two motors H4 and H are adapted to be energized to rotate in one direction or the other by means of a relay I" or a relay III which .is energized in response to discharge of electronic valve tubes. the plates H0 and H0a of which are shown. Assuming that the relay I I1 is actuated in response to discharge of the electronic valve tube, a circuit is closed through the winding of the motor I II which corresponds to motor 00 and the disc I02 is driven. Upon one complete rotation of this disc the normally open switch H2 is closed, thus completing a circuit through the winding of the motor 00 and driving the shaft I0l. At the position corresponding to zero position or no resistance of the disc I02 which is driven by motor 00 the switch III will be open. Momentary closing of switch H2 which bridges across the contacts of switch III as the disc I02 moves from 9 to 0 position, energizes the motor 99 and causes it to rotate while the protuberance H0 on the disc III which is driven by motor H4 opens the circuit. However, by this time the switch III has closed since the protuberance I03 on disc I02 is driven by motor 99 has moved out 01 engagement with the switch III and this the motor 99 continues to run until the switch I H is again opened by the succeeding protuberance I03. This step by step rotation of the disc I02 by motor 00 continues without operation of motor H5 until the protuberance H0 which is driven by motor 00 closes the switch H2 associated therewith. Upon closing or the switch H2 the motor H5 is energized and the disc I02 driven thereby is moved forward one step. Thus this arrangement of the motor and switches acts similarly to a Geneva movement in a mechanical register in that the lowest valve disc may rotate intermittently or continuously while the higher value discs are rotated one step for each complete revolution of each successively lower value disc. Reversal of the motors H4, 99 and I I5, by actuation of the relay II6, permits deductions to be made.

This operation of the switching mechanism for varying the resistances in the arms of the bridge to maintain the bridges in balance may likewise be utilized to indicate the various totals or odds at any instant. In its simplestform, the indicating means may consist of an indicating drum or wheel II9 bearing numerals from to 9 which is mounted on the shaft IM and rotates with the disc I02.

The shaft IOI may be extended in order to include a series of commutator and resistance devices similar to the elements I04, I and I09 which are disclosed in Figures 5 and 6 in order to provide for switching of the various resistances in the dummy banks of resistances in the bridges A and B to correspond to the values of the resistances I6-I9 and 283I and common source of power and thus assuring that each of these banks of resistors and associated switching arrangements are maintained at equal value at all times.

Th resistance varying and indicating device described above is' actuated by the thermionic valve circuit 21 which is responsive to voltage variations in the opposed arms of the bridge. A typical circuit 21 for controlling the resistance varying and indicating device is disclosed in i In this circuit the signals from the Figure 8. bridge are fed to the input terminals I and I 2I of a balanced two stage direct current amplifier of conventional type, comprising the first stage tubes I22 and I23, the second stage tubes I24 and I25 and their associated circuits, as shown in Figure 8. The output of the a plifier is supplied from the output terminals 26 and I2I to the control grids of a pair of thyratron tubes I28 and I29, respectively, in the plate circuits of which are located the relays H6 and I I1, respectively, for operating the bridge motors.

Alternating current is supplied through a conductor I30 to the plate circuits of the thyratron tubes I28 and I29 from a transformer I3I, th primary of which is connected to an alternating current source. The cathodes of the thyratrons I28 and I29 are tied together and are connected through a conductor I32 to a tap I33 on the secondary winding of the transformer I3I, thus completing the circuit.

The grid of thyratron tube I29 is provided with bias voltage from a voltage divider I34, one end of which is connected to the secondary terminal I35 of the transformer I3l, the other end being connected to the tap I33. Likewise, bias voltage for the thyratron tube I28 is provided by a voltage divider I35a which is connected in parallel with voltage divider I35.

Direct current voltage for the amplifier may be obtained from a conventional rectifier-filter circuit which includes a transformer I36, the primary of which is connected to an alternating current source. The secondary terminals I31 and I38 of the transformer I36 are connected to the plates of a full-wave rectifier tube I39, providing a pulsating D. C. voltage across the conductors I40 and MI. The pulsating D. C. voltage is filtered in the conventional manner by a filter circuit including the shunt condensers I42 and I43 and a series inductance I44 providing a continuous D. .C. voltage across the bleeder resistor I45, which is tapped to supply the necessary grid bias and plate voltages for the amplifier tubes I22, I23, I24 and I20.

When the bridge is balanced, zero voltage exists across the amplifier input terminals I20 and I2I, and the currents flowing in the plate circuits of the input tubes I22 and I23 are of equal magnitude. Since these plate currents flow through the plate resistors I46 and I460, respectively, the votlage drops across these resistors are also of equal magnitude, but they are opposite, so that no signal is applied to the grids of the tubes I24 and I26, and both of the relays H6 and III are inoperative.

However, if the bridge is unbalanced, and the signal voltage impressed across the input terminals I20 and I2I of the'amplifier is of such polarity that terminal I 20 is positive and terminal I2I is negative the following operation will take place. It will be apparent on inspection of the amplifier circuit that this will decrease the negative bias on the tube I 22 so that the current flowing in its plate circuit will increase. Inasmuch as the plate current flows through the plate resistor I46, the voltage drop across the resistor will increase.

Meanwhile, the tube I23 is biased more negatively by the voltage impressed on the terminals I20 and I2I, so that the current in its plate circuit is reduced, and the voltage drop across its plate resistor I46a is correspondingly reduced. Thus a D. C. voltage now exists across the terminals I41 and I48 which is the algebraic sum of the voltages across the plate resistors I46 and I46a.

This voltage is impressed across the grids of the tubes I24 and I25, producing similar changes in the voltage drops across the plate resistors I49 and I50 with the result that the voltage output at the amplifier terminals I26 and I21 is substantially greater than the voltage impressed on the input termihals I20 and I2l.

The polarity of the amplified voltage is such that the output terminal I26 is positive and terminal I21 is negative. The application of this amplified voltage from the output terminals I26 and I2I to the grids of th thyratron tubes I28 and I29 causes the tube I28 to ignite, permitting current to flow through the relay H6 and operating the bridge motor 99 for inserting resistance in the bridge. When the bridge has been restored to balance, the voltage at the input terminals I20 and I2I of the amplifier will be brought to zero, thus extinguishing the thyratron tube I28, deenergizing its relay H6, and stopping the bridge motor 99.

It will be readily apparent on inspection of the amplifier circuit, that if the polarity of the voltage impressed on the amplifier input terminals I20 and I2I is such that terminal I2I is positive and terminal I22 is negative. thyratron tube I29 will be ignited, causing plate current to fiow through relay II I'and energizing motor 99 for subtracting resistance from the bridge. When the bridge is again balanced, the thyratron tube I29 will be extinguished, thus d'eenergizing the relay III and stopping the motor 99.

Summarizing the operation of the device briefly, when a key at one of the stations I0 or II is depressed; controlling for example the resistance of device I2, the resistance in one arm of the bridge A is increased by rotation of the disc 85. Similarly, if one of the resistance devices, for ex- 1 ample device I3, is actuated to increasethe resist dered unbalanced, the signal voltages impressed upon the amplifiers A associated with each bridge at the input terminals lil'and |2l thereof are varied from equality and the voltage will be rendered positive at terminal I" and negative at terminal III. This unequal or voltage condition causes the thyratron tube In to ignite, actuating the relay Ill and causing the motors as to operate, thereby increasing the value of one or more of the resistances It to I! of bridge A and one or more of the resistances It to 3| of bridge B. The corresponding indicating drums are rotated at the same time to indicate the numerical value represented by the resistances in the bridges A and B.

The members II also drive variable resistances in the arms 01' bridges C, D and E and these bridges will become unbalanced.

In the bridge 0, the resistances 32 to a in one arm thereof are connected in series and inasmuch as they correspond to the resistances It to I! and 28 to II, the increase in value oi. the resistances 32 to it corresponds to the total increase in resistance of the resistance devices It, I3, I! and I 8. The bridge C, therefore, is the grand totals bridge and being unbalanced, will actuate the amplifier relay A to cause the motor driven register disclosed in Figs. 5, 6 and 7 to increase -the value of the resistances I! to It, thereby bringing the bridge into balance and indicating the grand total.

The odds bridges D and E are rendered unbalanced by the balancing of bridges A and B unless equal amounts are bet at stations I! and II, for the reason that the resistances ii to 54 correspond to the resistances it to I! and the resistances 41 to II correspond to the resistances as to l l The bridges D and E. being ratio bridges, are brought into balance. it unbalanced. by the resistances I! to I! and I! to 13 respectively, which are varied in resistance by means 0! the amplifler relays A and the motor controlled register disclosed in Figs. to 7, as described previously. The indicating drums Ill 0! the motor registers will indicate the ratios oi! the amount bet on the horses, thus providing odds, or if desired the profit on each dollar bet on a horse, depending upon the presence and value of the resistances I in bridges D and E.

Thus, the device is capable of indicating grand totals, horse totals and odds or profits on each bet.

From the foregoing it will be apparent that devices oi the type described above are capable oi! automatic operation to add, subtract, divide or multiply and that a simple construction has been provided which is particularly suitable for parimutuel betting.

It will be understood. that other equivalent devices may be substituted, in part or wholly, tor the indicating and resistance varying devices and that other variations may be made in the device without departing from the invention. Accordingly, the above described embodiments of the invention sh'ould be considered as illustrative, only, and not as limiting the scope of the following claims.

I claim:

1. A calculating device comprising a resistance bridge circuit having opposed arms, means for varying the resistance in one arm of said bridge circuit in equal amounts corresponding to a unit of numerical value, means for varying the resistance in another opposed arm in amounts corresponding to said unit 01' numerical value, a second resistance bridge circut having opposed arms, means for varying the resistance in one arm or said second bridge circuit in equal amounts corresponding to said unit of numerical value, means for varying the resistance in another opposed arm of the second bridge circuit in amounts corresponding to said unit of numerical value, means responsive to inequalities in each oi said bridge circuits for actuating the means for varying the resistance in the said another arms of said first and second bridge circuit to equalize the resistances in the arms of said bridge circuits; 2. third bridge circuit having opposed arms, means actuated by the means responsive to inequalities in each of said first and second bridge circuits for varying the resistance in one arm of the third bridge circuit to maintain it equal to the sum of the resistances in said other arms oi said first and second bridge circuits, means for varying the resistance in another opposed arm of said third bridge circuit, means responsive to inequalities in resistance in the arms of the third bridge circuit for actuating the means for varying the resistance in said another arm to equalize the resistances in said arms.

2. The devices set forth in claim 1 comprising indicating means associatedwith each of said bridge circuits actuated in response to variation in the resistance in said other arms oi said bridges for indicating the units of numerical value corresponding to said resistance.

3. A calculating device comprising a first resistance bridge circuit having opposed arms, means for varying the resistance in one arm of said bridge circuit in progressively equal amounts corresponding to a predetermined unit of numerical value, means connected between said opposed arms responsive to inequalities in the resistance in the arms of said bridge circuit for varying the resistance in another arm of said bridge circuit to equalize the resistance in said arms; a second resistance bridge circuit having opposed arms, means for varying the resistance in one arm of said second bridge circuit in amounts corresponding to said unit of numerical value, means connected between said opposed arms of saidsecond bridge circuit responsive to inequalities in the arms of said second bridge circuit for varying the resistance in another arm to equalize the resistance in the arms of said second bridge circuit; a third resistance bridge circuit having opposed arms, means including the means for varying the resistances in said another arms oi said first and second bridge circuits for varying the resistance in one arm of said third bridge circuit to equal the sum of the resistances in said other arms of said third bridge circuit and means for equalizing the resistances in said one and said another arms of said third bridge circuit.

4. The device set forth in claim 3 comprising separate indicating means associated with each bridge circuit, and actuated in response to operation of the means for varying the resistances of said other arms for indicating the corresponding numerical value oi. the resistance in said one arm of each bridge.

5. The calculating device set forth in claim 3 comprising a fourth resistance bridge circuit having opposed arms, means for'varying the resistance in one arm of said bridge circuit to render it equal to the resistance in said another arm 01 said first bridge circuit, means for varying the resistance in the other arm of said fourth bridge circuit to render it equal to the resistance in said another arm of said second bridge circuit, and means for determining the ratio of the resistances in the arms of said third bridge circuit.

6. A calculating device comprising -a first resistance bridge circuit having opposed arms, means for varying the resistance in one arm of said circuit in amounts corresponding to units of numerical value, means for varying the resistance in an opposed arm of said circuit to equalize the resistances in said opposed arms, a motor for actuating the last-named means, a relay circuit responsive to inequalities in resistance in said circuit for actuating said motor; a second bridge circuit having opposed arms, means for varying the resistance in one arm of said second circuit in amounts corresponding to units of numerical value, means for varying the resistance in an opposed arm of said second circuit to equalize the resistances in said opposed arms, a motor for actuating the lastnamed means, a relay circuit responsive to inequalities in resistance in said second circuit for actuating said motor, and a third bridge circuit having opposed arms, means connected in series actuated by said motors for varying the resistance in one armvof said third circuit to correspond to the sum of the resistances in said another arm of said first and second circuits, means for varying the resistance in another arm of said third circuit, a motor for actuating the lastnamed means, and a relay circuit responsive to inequalities in the resistances in the opposed arms 01' said third circuit for controlling said third circuit motor to equalize the resistances in said arms, and separate indicating means actuated by each of said motors for displaying the numerical values corresponding to the resistances in the arms of said bridges.

of the bridge circuit step by step to equalize the resistances in said arms; a second Wheatstone bridge circuit, including means for increasing the resistance in one arm of said second circuit step by step, means including a motor responsive to the increase of resistance in said one arm of said second circuit for increasing the resistance in an opposed arm of said second circuit; and a third bridge circuit including means actuated by said motor for increasing the resistance in one arm of said third circuit proportionately to the increases in resistances in said one arms of said first and second bridge circuits and means including a motor responsive to the increase in resistance in said one arm of said third circuit for equalizing resistances in said arms.

8. The calculating device set forth in claim 'I in which the means including a motor responsive to the increase in resistance in said one arm comprises thermionic ampliiying means, and a relay circuit for starting and stopping said motor controlled by said amplifying means.

9. The calculating device set forth in claim 7 comprising a separate indicator calibrated in numerical values corresponding to the resistances in said another arms of said bridge circuits actuated by each or said motors. I .i a, v

GEORGE H. GORDON. 

